Improvement in methods of blasting rock



lJ. BRODIE &'S. H. WHEELER.

lmprovemeht in Method f Blasting Rock.

N0. 131,995. Patented Oct. 8, 1872.*

UNITED STATES PATENT OEEIcE.

JAMES EnoDIEl AND sAMUEL E. WHEELER, or SAN EEANcIsco, GAL.

l IMPROVEMENT IN MErIHoDsfoF BLAsTlNc-s RocK.r

Specilcation forming part of Letters Patent No. 131,995, dated October8, 1872.

To all whom it may concern:

Be it known that we, JAMES BRoDLE and SAMUEL H WHEELEInV of the city ofSan Francisco, county of San Francisco, and State of California, haveVinvented an Improvedoriginalface ofthe rock is reached. This plan isexpensive, in consequence of thetime spent in removing and replacing thedrilling apparatus and the excavating incident to each step ofthe work.It has, hence, been proposed to drill the hole at the outset to thedepth of a hundred` feet ormore, or to the whole depth to which it isproposed to excavate, and' to fill it with iron bolts or -plugs up tothe point where itis proposed to locate the iirst charge.

` For the second charge the plugs are removed to aI cert-ain additionaldepth, and so on until the work of blastin g is'eomplete, the dbris orbroken rock being removed subsequent to each explosion. But seriousobjections lie against this method, so that, as far as We are aware, itspracticability has not been established.

Our invention obviates these objections; and

to this end it consists mainly in the employment-of sand, or equivalentloose material, to constitute a lilling for the drill-hole.

In practice we drill holes in a shaft toa depth of one hundred feet fromthe face of the rock and lill them up to within three feet from the facewith loose sand, and place the charges of explosive material in theholes on the top of the sand. After the charges have been ex ploded andthe detached rock cleared away we remove the sand from the holes to adepth of three feet and insert other charges, which We explode, andcontinue thus until the rock has been excavated tothe bottom of theholes. We then make other holes to a depth of one :hundred feet andproceed as before, and so on to any depth required, until we haveexcavated to the bottom-of the shaft.

The use of sand is highly advantageous, mainly for the followingreasons: First, it is readily accessible in nearly all localities, andcosts little more than the labor involved in digging it; second, itforms a solid, impene trable bed upon which to rest the charge, so thatthe explosive force of the latter may be 'expended at the desired pointwith the greatest eiect; third, it is easily placed in or removed fromthe drill-hole by simple means, or without the aid of tongs,grappling-irons, or any other peculiar apparatus. H

We claim as our-as invention- The method of `blastingrock by means ofsand as a filling material for the drill-hole,

said hole being first bored to a depth requisite for insertion andexplosion of several charges,

and the sand, or other equivalent material, be-

ing removed therefrom subsequent to each exi plosion to enable thesucceeding charge to be placed in the hole to the depth required for thenext explosion, the sand in every instance forming a bed for the charge,as specied.

' J AMES BRODIE. i

SAMUEL H. WHEELER. Witnesses:

WILLIAM MOODY, 'Wt Z. BROMLEY.

